Removed code for spline interpolation.

config.h

@@ -26,7 +26,6 @@
 
 #include "midinotes.h"
 #include <Arduino.h>
-#include "spline.h"
 
 // ATTENTION! For better latency you have to redefine AUDIO_BLOCK_SAMPLES from
 // 128 to 64 in <ARDUINO-IDE-DIR>/cores/teensy3/AudioStream.h
@@ -60,10 +59,6 @@
 #define CHORUS_WAVEFORM WAVEFORM_TRIANGLE // WAVEFORM_SINE WAVEFORM_TRIANGLE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE
 #define CHORUS_MODULATOR_FILTER_FRQ 500
 #define CHORUS_MODULATOR_FILTER_Q 0.7
-//#define CHORUS_INTERPOLATION_MODE 0       // no interpolation
-//#define CHORUS_INTERPOLATION_MODE 1       // linear interpolation
-//#define CHORUS_INTERPOLATION_MODE Catmull   // spline interpolation
-#define CHORUS_INTERPOLATION_WINDOW_SIZE 5  // only uneven numbers bigger than 3!!!
 
 //*************************************************************************************************
 //* DEBUG OUTPUT SETTINGS
@@ -73,7 +68,7 @@
 #define SERIAL_SPEED 38400
 #define SHOW_XRUN 1
 #define SHOW_CPU_LOAD_MSEC 5000
-#define DEBUG_AUDIO 50
+//#define DEBUG_AUDIO 50
 
 //*************************************************************************************************
 //* HARDWARE SETTINGS

effect_modulated_delay.cpp

@@ -25,7 +25,6 @@
 #include <Audio.h>
 #include "limits.h"
 #include "effect_modulated_delay.h"
-#include "spline.h"
 #include "config.h"
 
 /******************************************************************/
@@ -87,10 +86,6 @@ void AudioEffectModulatedDelay::update(void)
     float mod_idx;
     float mod_number;
     float mod_fraction;
-#ifdef CHORUS_INTERPOLATION_MODE
-    int8_t j;
-    uint8_t c;
-#endif
 
     bp = block->data;
     mp = modulation->data;
@@ -106,21 +101,7 @@ void AudioEffectModulatedDelay::update(void)
       // The index is located around the half of the delay length multiplied by the current amount of the modulator
       mod_idx = _delay_offset + ((float(*mp) / SHRT_MAX) * _modulation_intensity);
       mod_fraction = modff(mod_idx, &mod_number);
-      // Generate a an array with the size of CHORUS_INTERPOLATION_WINDOW_SIZE of x/y values around mod_idx for interpolation
+      
-#ifdef CHORUS_INTERPOLATION_MODE
-      // spline interpolation
-      c_mod_idx = _circ_idx - int(mod_idx); // This is the pointer to the value in the circular buffer at the current modulation index
-      for (j = (CHORUS_INTERPOLATION_WINDOW_SIZE / -2), c = 0; j <= (CHORUS_INTERPOLATION_WINDOW_SIZE / 2); j++, c++)
-      {
-        int16_t jc_mod_idx = (c_mod_idx + j) % _delay_length; // The modulation index pointer plus the value of the current window pointer
-        if (jc_mod_idx < 0) // check for negative offsets and correct them
-          y[c] = float(_delayline[_delay_length + jc_mod_idx]);
-        else
-          y[c] = float(_delayline[jc_mod_idx]);
-        x[c] = float(j);
-      }
-      *bp = int(round(spline->value(mod_fraction))); // use spline interpolated value
-#else
       // linear interpolation
       c_mod_idx = _circ_idx - round(mod_idx);
       if (mod_idx < 0.0) // c_mod_idx is the pointer to the value in the circular buffer at the current modulation index
@@ -144,7 +125,7 @@ void AudioEffectModulatedDelay::update(void)
         idx[1] = c_mod_idx + 1;
       }
       *bp = round(float(_delayline[idx[0]]) * (1.0 - mod_fraction) + float(_delayline[idx[1]]) * mod_fraction);
-#endif
+
       bp++; // next audio data
       mp++; // next modulation data
       _circ_idx++; // next circular buffer index

effect_modulated_delay.h

@@ -57,13 +57,7 @@ class AudioEffectModulatedDelay :
     uint16_t _modulation_intensity;
     uint16_t _delay_length;
     int16_t c_mod_idx;
-#ifdef CHORUS_INTERPOLATION_MODE
-    float x[CHORUS_INTERPOLATION_WINDOW_SIZE];
-    float y[CHORUS_INTERPOLATION_WINDOW_SIZE];
-    Spline* spline;
-#else
     uint16_t idx[2];
-#endif
 };
 
 #endif

spline.cpp

@@ -1,111 +0,0 @@
-// From: https://raw.githubusercontent.com/kerinin/arduino-splines/master/spline.cpp
-#include "Arduino.h"
-#include "spline.h"
-#include <math.h>
-
-Spline::Spline(void) {
-  _prev_point = 0;
-}
-
-Spline::Spline( float x[], float y[], int numPoints, int degree )
-{
-  setPoints(x,y,numPoints);
-  setDegree(degree);
-  _prev_point = 0;
-}
-
-Spline::Spline( float x[], float y[], float m[], int numPoints )
-{
-  setPoints(x,y,m,numPoints);
-  setDegree(Hermite);
-  _prev_point = 0;
-}
-
-void Spline::setPoints( float x[], float y[], int numPoints ) {
-  _x = x;
-  _y = y;
-  _length = numPoints;
-}
-
-void Spline::setPoints( float x[], float y[], float m[], int numPoints ) {
-  _x = x;
-  _y = y;
-  _m = m;
-  _length = numPoints;
-}
-
-void Spline::setDegree( int degree ){
-  _degree = degree;
-}
-
-float Spline::value( float x )
-{
-  if( _x[0] > x ) { 
-    return _y[0]; 
-  }
-  else if ( _x[_length-1] < x ) { 
-    return _y[_length-1]; 
-  }
-  else {
-    for(int i = 0; i < _length; i++ )
-    {
-      int index = ( i + _prev_point ) % _length;
-      
-      if( _x[index] == x ) {
-        _prev_point = index;
-        return _y[index];
-      } else if( (_x[index] < x) && (x < _x[index+1]) ) {
-        _prev_point = index;
-        return calc( x, index );
-      }
-    }    
-  }
-}
-
-float Spline::calc( float x, int i )
-{
-  switch( _degree ) {
-    case 0:
-      return _y[i];
-    case 1:
-      if( _x[i] == _x[i+1] ) {
-        // Avoids division by 0
-        return _y[i];
-      } else {
-        return _y[i] + (_y[i+1] - _y[i]) * ( x - _x[i]) / ( _x[i+1] - _x[i] );      
-      }
-    case Hermite:
-      return hermite( ((x-_x[i]) / (_x[i+1]-_x[i])), _y[i], _y[i+1], _m[i], _m[i+1], _x[i], _x[i+1] );
-    case Catmull:
-      if( i == 0 ) {
-        // x prior to spline start - first point used to determine tangent
-        return _y[1];
-      } else if( i == _length-2 ) {
-        // x after spline end - last point used to determine tangent
-        return _y[_length-2];
-      } else {
-        float t = (x-_x[i]) / (_x[i+1]-_x[i]);
-        float m0 = (i==0 ? 0 : catmull_tangent(i) );
-        float m1 = (i==_length-1 ? 0 : catmull_tangent(i+1) );
-        return hermite( t, _y[i], _y[i+1], m0, m1, _x[i], _x[i+1]);        
-      }
-  }
-}
-
-float Spline::hermite( float t, float p0, float p1, float m0, float m1, float x0, float x1 ) {
-  return (hermite_00(t)*p0) + (hermite_10(t)*(x1-x0)*m0) + (hermite_01(t)*p1) + (hermite_11(t)*(x1-x0)*m1);
-}
-float Spline::hermite_00( float t ) { return (2*pow(t,3)) - (3*pow(t,2)) + 1;}
-float Spline::hermite_10( float t ) { return pow(t,3) - (2*pow(t,2)) + t; }
-float Spline::hermite_01( float t ) { return (3*pow(t,2)) - (2*pow(t,3)); }
-float Spline::hermite_11( float t ) { return pow(t,3) - pow(t,2); }
-
-float Spline::catmull_tangent( int i ) 
-{ 
-  if( _x[i+1] == _x[i-1] ) {
-    // Avoids division by 0
-    return 0;
-  } else {  
-    return (_y[i+1] - _y[i-1]) / (_x[i+1] - _x[i-1]);    
-  } 
-}

spline.h

@@ -1,43 +0,0 @@
-// From  https://raw.githubusercontent.com/kerinin/arduino-splines/master/spline.h
-/*
-  Library for 1-d splines
-  Copyright Ryan Michael
-  Licensed under the LGPLv3 
-*/
-#ifndef spline_h
-#define spline_h
-
-#include "Arduino.h"
-
-#define Hermite 10
-#define Catmull 11
-
-class Spline
-{
-  public:
-    Spline( void );
-    Spline( float x[], float y[], int numPoints, int degree = 1 );
-    Spline( float x[], float y[], float m[], int numPoints );
-    float value( float x );
-    void setPoints( float x[], float y[], int numPoints );
-    void setPoints( float x[], float y[], float m[], int numPoints );
-    void setDegree( int degree );
-    
-  private:
-    float calc( float, int);
-    float* _x;
-    float* _y;
-    float* _m;
-    int _degree;
-    int _length;
-    int _prev_point;
-    
-    float hermite( float t, float p0, float p1, float m0, float m1, float x0, float x1 );
-    float hermite_00( float t );
-    float hermite_10( float t );
-    float hermite_01( float t );
-    float hermite_11( float t );
-    float catmull_tangent( int i );
-};
-
-#endif